General Information

Key Points for This Section

Nausea and vomiting are serious side effects of cancer therapy.

Nausea is an unpleasant wavelike feeling in the back of the throat and/or stomach that may lead to vomiting. Vomiting is throwing up the contents of the stomach through the mouth. Retching is the movement of the stomach and esophagus without vomiting and is also called dry heaves. Although treatments have improved, nausea and vomiting are still serious side effects of cancertherapy. Some patients are bothered more by nausea than by vomiting.

Nausea and vomiting must be controlled to maintain the patient's treatment and quality of life.

It is very important to prevent and control nausea and vomiting in patients with cancer, so that they can continue treatment and perform activities of daily life. Uncontrolled nausea and vomiting can cause the following:

Anticipatory nausea and vomiting: If a patient has had nausea and vomiting after the previous three or four chemotherapy treatments, he or she may have anticipatory nausea and vomiting. The smells, sights, and sounds of the treatment room may remind the patient of previous times and may trigger nausea and vomiting before a new cycle of chemotherapy has even begun.

Acute nausea and vomiting: Usually happen within 24 hours after beginning chemotherapy

Delayed nausea and vomiting: Happen more than 24 hours after chemotherapy. Also called late nausea and vomiting.

Chronic nausea and vomiting: In patients with advanced cancer, chronic nausea and vomiting may be caused by the following:

Key Points for This Section

Anticipatory nausea and vomiting may occur after several treatment sessions.

Anticipatory nausea and vomiting occur in some patients after they have had several courses of treatment. This is caused by triggers, such as odors in the therapy room. For example, a person who begins chemotherapy and smells an alcohol swab at the same time may later have nausea and vomiting at the smell of alcohol alone. The more chemotherapy sessions a patient has, the more likely it is that anticipatory nausea and vomiting will develop. The following may make anticipatory nausea and vomiting more likely:

The earlier that anticipatory nausea and vomiting is identified, the more effective treatment may be.

Treatment of anticipatory nausea and vomiting is more likely to work when symptoms are treated early. Although antinausea drugs do not seem to help, the following types of treatment may decrease symptoms:

Acute and delayed nausea and vomiting are usually treated with drugs.

Acute and delayed nausea and vomiting are usually treated with antinausea drugs. Some types of chemotherapy are more likely to cause acute nausea and vomiting. Drugs may be given before each treatment to prevent nausea and vomiting. After chemotherapy, drugs may be given to prevent delayed vomiting. Some drugs last only a short time in the body and need to be given more often. Others last a long time and are given less often.

Treatment of nausea and vomiting in advanced cancer includes ways to keep bowel habits regular.

In patients with advanced cancer, constipation is one of the most common causes of nausea. To prevent constipation, it is important that a regular bowel routine be followed, even if the patient isn't eating. Laxatives that soften the stool or stimulate the bowel may help prevent constipation, especially if the patient is being treated with opioids for cancer pain. Patients with advanced cancer usually cannot handle high-fiberdiets or laxatives with psyllium or cellulose that need to be taken with a lot of fluids.

Nausea and vomiting are sometimes caused by a blocked bowel.

Patients who have advanced cancer may have a blocked bowel caused by a tumor. If the bowel is partly blocked, the doctor may put a nasogastric tube through the nose and esophagus into the stomach to make a temporary passage. If the bowel is completely blocked, the doctor may insert a gastrostomy tube through the wall of the abdomen directly into the stomach to relieve the build-up of fluid and air. Also, medicines and liquids can be given directly into the stomach through the tube.

Sometimes, the doctor may create an ileostomy or colostomy by bringing part of the small intestine or colon through the abdominal wall to form an opening on the outside of the body. For certain colorectal blockages, an expandable metal tube called a stent may be put in, to open the blocked area.

Medicines may also be used to treat nausea and vomiting and relieve pain.

Radiation Therapy and Nausea and Vomiting

Key Points for This Section

Radiation therapy may cause nausea and vomiting.

Radiation therapy may cause nausea and vomiting, especially in patients who are receiving radiation therapy to the gastrointestinal tract, liver, or brain. The risk for nausea and vomiting increases as the dose of radiation and the size of the area being treated increase. Nausea and vomiting caused by radiation therapy usually occur one-half hour to several hours after treatment. Patients may have fewer symptoms on days they do not have radiation therapy.

Changes to This Summary (12/12/2013)

The PDQcancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

Editorial changes were made to this summary.

About This PDQ Summary

About PDQ

Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.

PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government’s center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.

Purpose of This Summary

This PDQ cancer information summary has current information about the causes and treatment of nausea and vomiting (emesis) (N&V). It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.

Reviewers and Updates

Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Date Last Modified") is the date of the most recent change.

Clinical Trial Information

A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Clinical trials are listed in PDQ and can be found online at NCI's Web site. Many cancer doctors who take part in clinical trials are also listed in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER (1-800-422-6237).

Permission to Use This Summary

PDQ is a registered trademark. The content of PDQ documents can be used freely as text. It cannot be identified as an NCI PDQ cancer information summary unless the whole summary is shown and it is updated regularly. However, a user would be allowed to write a sentence such as “NCI’s PDQ cancer information summary about breast cancer prevention states the risks in the following way: [include excerpt from the summary].”

Images in this summary are used with permission of the author(s), artist, and/or publisher for use in the PDQ summaries only. If you want to use an image from a PDQ summary and you are not using the whole summary, you must get permission from the owner. It cannot be given by the National Cancer Institute. Information about using the images in this summary, along with many other images related to cancer can be found in Visuals Online. Visuals Online is a collection of more than 2,000 scientific images.

Contact Us

More information about contacting us or receiving help with the Cancer.gov Web site can be found on our Contact Us for Help page. Questions can also be submitted to Cancer.gov through the Web site’s Contact Form.

Questions or Comments About This Summary

If you have questions or comments about this summary, please send them to Cancer.gov through the Web site’s Contact Form. We can respond only to email messages written in English.

Get More Information From NCI

Call 1-800-4-CANCER

For more information, U.S. residents may call the National Cancer Institute's (NCI's) Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237) Monday through Friday from 8:00 a.m. to 8:00 p.m., Eastern Time. A trained Cancer Information Specialist is available to answer your questions.

Chat online

The NCI's LiveHelp® online chat service provides Internet users with the ability to chat online with an Information Specialist. The service is available from 8:00 a.m. to 11:00 p.m. Eastern time, Monday through Friday. Information Specialists can help Internet users find information on NCI Web sites and answer questions about cancer.

Write to us

For more information from the NCI, please write to this address:

NCI Public Inquiries Office

9609 Medical Center Dr.

Room 2E532 MSC 9760

Bethesda, MD 20892-9760

Search the NCI Web site

The NCI Web site provides online access to information on cancer, clinical trials, and other Web sites and organizations that offer support and resources for cancer patients and their families. For a quick search, use the search box in the upper right corner of each Web page. The results for a wide range of search terms will include a list of "Best Bets," editorially chosen Web pages that are most closely related to the search term entered.

There are also many other places to get materials and information about cancer treatment and services. Hospitals in your area may have information about local and regional agencies that have information on finances, getting to and from treatment, receiving care at home, and dealing with problems related to cancer treatment.

Find Publications

The NCI has booklets and other materials for patients, health professionals, and the public. These publications discuss types of cancer, methods of cancer treatment, coping with cancer, and clinical trials. Some publications provide information on tests for cancer, cancer causes and prevention, cancer statistics, and NCI research activities. NCI materials on these and other topics may be ordered online or printed directly from the NCI Publications Locator. These materials can also be ordered by telephone from the Cancer Information Service toll-free at 1-800-4-CANCER (1-800-422-6237).